There has conventionally been known a battery in which at least two electrode plates having one polarity and at least one electrode plate having the other polarity are alternately superposed on each other with separator layers therebetween, thereby to form an electrode assembly, which is housed in a battery vessel constituted by a metallic outer case and a metallic closure cover joined to this metallic outer case, said electrode plates having said one polarity being electrically connected to said battery vessel and said at least one electrode plate having said other polarity being electrically connected to a collector rod, which is projected from said closure cover through an insulating member. In such conventional battery, the projection of the collector rod from the closure cover is realized in such a manner that a through-bore is formed in the closure cover and the collector rod passes, at one end thereof, through this through-bore through the insulating member and a nut is threaded to a screw groove formed in this projected portion of the collector rod, thereby to fix the collector rod and the closure cover to each other. However, such construction presents a defect that the nut is loosened so that high air-tightness cannot be provided in the battery vessel.
Furthermore, in such conventional battery, the electric connection of the electrode plates having one polarity to the outer case is performed in such a way that the outer diameters of the electrode plates having said one polarity are the substantially same as the inner diameter of the outer case, so that the peripheries of the electrode plate shaving said one polarity come in contact with the inner wall of the outer case when such electrode plates are housed in the outer case. However, such arrangement requires to pay much attention to dimensional accuracy of the outer diameters of the electrode plates having said one polarity. That is, if the outer diameters of the electrode plates having said one polarity are relatively small with respect to the inner diameter of the outer case, the contact of the electrode plates having said one polarity with the outer case is not sufficient, thereby to reduce the effect of current collecting, although the battery assembling work is facilitated. On the other hand, if the outer diameters of the electrode plates having said one polarity are relatively large with respect to the inner diameter of the outer case, there is a possibility of the peripheries of such electrode plates falling into pieces at the assembling time and therefore the battery assembling work becomes difficult.